And, as Third Way's Matt Bennett pointed out to me, polls show voters often are more moderate than their politicians, even in deep blue or bright red states.
On many issues the country is sharply divided, as it was between Obama and Mitt Romney (Obama won just 51.1 percent of votes).
And while congressional gerrymandering amplifies the effect of the division, even fair redistricting would not bridge the chasm, as Rob Richie explained in a Washington Post op-ed last fall. (Richie's solution: Create multi-member House districts, so that the minority party in any given region could elect at least one out of three legislators.)
One result is that purported adherence to states' rights has become more situational than ever.
Red-staters want to ignore Roe v. Wade while insisting that the most permissive state's concealed-carry law be accepted across the country.
Advocates of gay marriage find themselves simultaneously against the federal Defense of Marriage Act because it doesn't recognize Massachusetts' primacy in allowing same-sex marriage and against California's ban on same-sex marriage because it violates the U.S. Constitution.
On some issues, liberal and conservative policies may get a chance to compete.
Will the well-funded schools of Maryland help attract business and maintain the state's prosperity despite higher taxes, as O'Malley maintains? Or will Brownback's tax cuts more effectively drive growth?
As red states resist Obamacare and blue states embrace it, where will people be healthier?
Unfortunately, across a range of issues, state diversity won't work very well.
A ban on assault weapons in Maryland is of limited use if you can buy a gun in Virginia. A married gay couple with children could risk custody if they move from Massachusetts to Mississippi.
But with Americans living in two separate worlds, that may be the reality we face for some time to come.
Hiatt is editorial page editor of The Washington Post.